/*
 * Copyright 2002-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.web.servlet.tags;

import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.web.util.JavaScriptUtils;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.BodyContent;
import javax.servlet.jsp.tagext.BodyTag;
import java.io.IOException;

/**
 * The {@code <escapeBody>} tag is used to escape its enclosed body content,
 * applying HTML escaping and/or JavaScript escaping.
 *
 * <p>Provides a "htmlEscape" property for explicitly specifying whether to
 * apply HTML escaping. If not set, a page-level default (e.g. from the
 * HtmlEscapeTag) or an application-wide default (the "defaultHtmlEscape"
 * context-param in web.xml) is used.
 *
 * <p>Provides a "javaScriptEscape" property for specifying whether to apply
 * JavaScript escaping. Can be combined with HTML escaping or used standalone.
 *
 * <table>
 * <caption>Attribute Summary</caption>
 * <thead>
 * <tr>
 * <th>Attribute</th>
 * <th>Required?</th>
 * <th>Runtime Expression?</th>
 * <th>Description</th>
 * </tr>
 * </thead>
 * <tbody>
 * <tr>
 * <td>htmlEscape</td>
 * <td>false</td>
 * <td>true</td>
 * <td>Set HTML escaping for this tag, as boolean value.
 * Overrides the default HTML escaping setting for the current page.</td>
 * </tr>
 * <tr>
 * <td>javaScriptEscape</td>
 * <td>false</td>
 * <td>true</td>
 * <td>Set JavaScript escaping for this tag, as boolean value.
 * Default is false.</td>
 * </tr>
 * </tbody>
 * </table>
 *
 * @author Juergen Hoeller
 * @see org.springframework.web.util.HtmlUtils
 * @see org.springframework.web.util.JavaScriptUtils
 * @since 1.1.1
 */
@SuppressWarnings("serial")
public class EscapeBodyTag extends HtmlEscapingAwareTag implements BodyTag {

    private boolean javaScriptEscape = false;

    @Nullable
    private BodyContent bodyContent;


    /**
     * Set JavaScript escaping for this tag, as boolean value.
     * Default is "false".
     */
    public void setJavaScriptEscape(boolean javaScriptEscape) throws JspException {
        this.javaScriptEscape = javaScriptEscape;
    }


    @Override
    protected int doStartTagInternal() {
        // do nothing
        return EVAL_BODY_BUFFERED;
    }

    @Override
    public void doInitBody() {
        // do nothing
    }

    @Override
    public void setBodyContent(BodyContent bodyContent) {
        this.bodyContent = bodyContent;
    }

    @Override
    public int doAfterBody() throws JspException {
        try {
            String content = readBodyContent();
            // HTML and/or JavaScript escape, if demanded
            content = htmlEscape(content);
            content = (this.javaScriptEscape ? JavaScriptUtils.javaScriptEscape(content) : content);
            writeBodyContent(content);
        }
        catch (IOException ex) {
            throw new JspException("Could not write escaped body", ex);
        }
        return (SKIP_BODY);
    }

    /**
     * Read the unescaped body content from the page.
     *
     * @return the original content
     * @throws IOException if reading failed
     */
    protected String readBodyContent() throws IOException {
        Assert.state(this.bodyContent != null, "No BodyContent set");
        return this.bodyContent.getString();
    }

    /**
     * Write the escaped body content to the page.
     * <p>Can be overridden in subclasses, e.g. for testing purposes.
     *
     * @param content the content to write
     * @throws IOException if writing failed
     */
    protected void writeBodyContent(String content) throws IOException {
        Assert.state(this.bodyContent != null, "No BodyContent set");
        this.bodyContent.getEnclosingWriter().print(content);
    }

}
